What do extinguishers having a zone of the color black contain?

Extinguishers that are marked with a black zone typically contain carbon dioxide (CO2). This type of extinguisher is specifically designed for use on fires involving electrical equipment and flammable liquids. Carbon dioxide works by displacing oxygen in the area of the fire, effectively suffocating it without leaving behind any residue, making it suitable for situations where equipment damage must be minimized.

This makes carbon dioxide extinguishers particularly valuable in environments like offices or control rooms, where sensitive electronics are present. In contrast, other types of extinguishers, such as those containing foam, water, or powder, have different applications and may not be suitable for fires involving electrical hazards. For instance, foam extinguishers are excellent for liquid fires, while water extinguishers are generally used for ordinary combustibles but are hazardous when used on electrical fires. Powder extinguishers can be versatile, tackling various types of fires, but they may not be as effective as CO2 extinguishers in specific situations with electrical equipment.